This demo shows a path made up of three cubic Bezier curve
segments. Each segment is defined by its two endpoints and two control points.
A control point determines the tangent at the corresponding endpoint. You can
drag the endpoints and the control points. If "Lock Control Point Pairs" is
specified, then the two control points associated with the endpoint where two
segments join are constrained to move together, resulting in a smooth curve.

Quadratic Bezier Curve

This demo shows a path made up of five quadratic Bezier curve
segments. Each segment is defined by its two endpoints and one control point. The
control point determines the tangent at both endpoints. You can drag the
control points and endpoints.